In order to explore the evolution law of molten pool flow and morphology of 42CrMo steel for crankshaft during laser remelting treatment

a two-dimensional simulation model with high fitting to the original morphology was established

and the surface of the sample was simulated and analyzed by finite element method under different laser powers

and the variation law of surface roughness and microhardness was compared and analyzed by experiments. The results show that the molten pool flow model can well predict the surface molten pool flow and surface micro-fluctuation of 42CrMo steel. The flow velocity in the molten pool increases first and then decreases. By adjusting the laser power

the surface remelting can be realized and the surface smoothness of the sample can be improved. After laser remelting treatment

the surface hardness of 42CrMo steel is significantly improved

which meets the requirements of crankshaft working conditions. The prediction results of surface roughness and weld pool depth by simulation model are basically consistent with the experimental results.